The present invention generally relates to an electric vacuum cleaner and more particularly, to a floor nozzle for use in a vacuum cleaner, provided therein with an agitator driven for rotation by a motor.
Conventionally, in a floor nozzle of this kind, rotating direction of the agitator is set to be only in one direction, and generally, when the operability of the floor nozzle is taken into account, such rotating direction is determined to be in a forward direction so as not to provide a resistance during advancing of the floor nozzle, while in the case where a dust rake-up characteristic of the agitator is taken into consideration, the agitator is set to be rotated in the opposite direction.
When the rotation of the agitator is selected to be in the former forward direction, it will be readily understood that a reaction force for advancing the nozzle is produced between the agitator and the floor, and thus, labor required for the advancing of the floor nozzle may be reduced by that extent.
Meanwhile, the selection of rotation of the agitator in the latter opposite direction is intended to improve the dust rake-up characteristic by the agitator even at the sacrifice of the operability during advancing of the floor nozzle. More specifically, in the above case, relative contact resistance between the floor, e.g. a carpet and the agitator is desirably increased, whereby dust or dirt adhering to filaments, etc. of the carpet may be favorably scraped off.
Incidentally, it has been known in the actual operation of the floor nozzle, that the movement of the floor nozzle is not limited to the advancing, but reciprocating movements repeating advancing and retreatment thereof are also included.
Therefore, the rotation of the agitator only in one direction as referred to above undesirably gives rise to a result contrary to the intended object during retreatment of the floor nozzle.
In order to overcome the problem as referred to above, there has been conventionally proposed an arrangement adapted to change-over the rotational direction of the motor according to advancement or retreatment of the floor nozzle. More specifically, in such arrangement, a play in the forward and backward directions is provided at junction between an extension pipe coupled with the suction side of the vacuum cleaner through a hose and the floor nozzle and movement of the junction within a range of said play according to the forward and backward operations of the floor nozzle is associated with change-over of a switch intended to alter the rotating direction of a motor.
By the known arrangement as described above, the agitator is to be rotated in the direction which will accomplish the intended object according to the advancing and retreating of the floor nozzle. However, in the above arrangement provided with the change-over switch, since an intermediate point for the change-over, i.e. a long OFF time is present, there are cases where the change-over of rotational directions of the motor is not favorably effected, while due to the fact that the change-over itself is to be effected slowly, an electric arc tends to be produced at contact portions, thus resulting in troubles such as adhesion by fusion, etc.